# Triple-Band Warm White-Light Emission from Type II Band-Aligned Aggregation-Induced Enhanced Emission Organic Cation-Incorporated Two-Dimensional Lead Iodide Perovskite

## TL;DR

A new 2D perovskite material emits warm white light with three color bands by combining organic and inorganic layers.

## Contribution

A fluorinated organic cation enables triple-band white-light emission in 2D perovskites through Type II energy alignment.

## Key findings

- The material emits warm white light with RGB triple-band photoluminescence under UV excitation.
- The FPCSA cation suppresses charge transfer and enables independent emission from organic and inorganic layers.
- This design offers a new approach for efficient single-phase white-light-emitting materials.

## Abstract

Single-phase white-light-emitting materials, particularly 2D hybrid organic–inorganic halide perovskites, have garnered significant attention due to their strong electron–phonon interactions, which lead to broad luminescence and a notable Stokes shift resulting from self-trapped exciton recombination. However, 2D lead iodide perovskites typically display these characteristics poorly, restricting their efficiency as white-light emitters. This study presents a 2D lead iodide perovskite that incorporates a fluorinated π-conjugated aggregation-induced enhanced emission luminophore, FPCSA, as a bulky organic cation to create a quasi-2D perovskite. The FPCSA cation establishes a Type II energy level alignment with the lead iodide layer in the 2D perovskite, and a significant energy offset effectively suppresses charge transfer, enabling independent emission from both the organic and inorganic layers while facilitating self-trapped exciton formation. Under 315 nm UV excitation, this material demonstrates warm white-light emission with RGB triple-band photoluminescence stemming from the electronically decoupled FPCSA and perovskite layers. These findings provide a promising new method for designing efficient single-phase white-light-emitting materials for optoelectronic applications.